6 4 



NA TURE 



[May 15, 1884 



tion of Civil Engineers, Mr. W. H. Preece, F.R.S., will give a 

 review of the work done by the Electrical Congresses of Paris, 

 and will describe the new units determined upon. 



The Lord Lieutenant of Ireland has appointed the following 

 Commissioners to inquire into the management of the Queen's 

 Colleges and Royal Universityin Ireland : — R. P. Carton, Q.C., 

 Mr. George Johnstone Stoney, F.R.S., Rev. Dr. Gerald Molloy, 

 Rector of the Catholic University, Mr. Win. Jack of Glasgow 

 University, and Surgeon-General Marsten. Mr. N. D. Murphy, 

 barrister, is appointed secretary. 



The Engineering Department of the Yorkshire College at 

 Leeds is about to be considerably enlarged, to admit of more 

 students at the classes, and towards this object Sir Andrew 

 Fairbairn, M. P., and Sir John Hawkshaw have each contributed 

 1000/. 



The steamer Alert, one of the vessels to be engaged in the 

 Greely Relief Expedition, sailed from New Yoik on May 10. 



The eminent Swedish astronomer, Prof. H. Gylden, at 

 present chief of the Stockholm Observatory, has been called to 

 the Professorship ol Practical Astronomy at Gottingen. 



Herr Augustin Gamel of Copenhagen has offered to 

 despatch the Dijmphna, under Lieut. Hovgaard, to Franz- Josef 

 Land in the summer of 1885, provided the Danish Government 

 will contribute part ol the expenses. No contribution will be 

 accepted from foreign nations. 



Prof. Nordenskjold has executed a detailed map of that 

 part of the east coast of Greenland which he visited last summer, 

 situated beyond Cape Dan, known from Lieut. Graah's journey. 

 The peninsula on which the cape is situated he has named 

 " King Christian's Island." and the harbour in which he landed 

 "King Oscar's Harbour." Several other points have been 

 named after celebrated Swedes and Danes. 



The Finnish Senate has petitioned the Czar that all members 

 of the forthcoming hydrographical expedition in the Baltic, which 

 will cost about 100,000 marks, shall be Finnish subjects, as so 

 little progress with such labours seems to be made under Russian 

 naval officers. 



The St. Petersburg Horticultural Exhibition and Botanical 

 Congress, which was deferred last year owing to the coronation 

 of the Czar, was opened on May 5. Mr. H. J. Elwes, F.L.S., 

 of Preston House, Cirencester, was requested by the Science and 

 Art Department to attend as the delegate on behalf of this 

 country, and has been accredited. 



Mr. J. E. Marr, M.A., Fellow of St. John's College, Cam- 

 bridge, has been appointed by the Council to lecture in geology. 



A violent shock of earthquake, having an undulatory cha- 

 racter, was felt at Spoleto at 8 o'clock on Friday night. The 

 bells were set ringing and the clocks stopped. On Saturday, at 

 9.50, a slight shock in the direction of from north-west to south- 

 east was felt at Cosenza, and at Paola a somewhat stronger shock 

 was felt. 



The additions to the Zoological Society's Gardens during the 

 past week include a Barbary Ape (Macacus inuus 9 ) from North 

 Africa, presented by the Countess of Craven ; a Moufflon (Oris 

 musimon I ) from Sardinia, presented by Col. Knox and the 

 Officers of the 1st Battalion Scots Guards ; a Common Raccoon 

 (Procyon lotor, white variety) from North America, presented by 

 Mr. F. J. Thompson ; a Ground Hornbill (Bttceros abyssinicus) 

 from West Africa, presented by Capt. Rupert La T. Lonsdale ; 

 a Gold Pheasant ( Thanmalea picta 9 ) from China, presented by 

 Mr. Frank Reed ; two Peregrine Falcons (Falco peregrinus), 

 European, presented by Lieut. -Col. Drummond Moray; two 

 Alligators (Alligator mississippiensis) from the Mississippi, pre- 



sented by Mrs. Andrade ; a Green Tree Frog (Hyla ariorea), 

 European, presented by Mr. G. W. Obicini, F.Z.S. ; twenty- 

 one River Lampreys (Petromyzon ftnviatilis) from British rivers, 

 presented by Mr. T. E. Gunn ; two Japanese Greenfinches 

 (Ligurinus sinicus 6 9 ) from Japan, two Common Crowned 

 Pigeons (Goura coronata) from New Guinea, purchased ; a 

 Canadian Porcupine (Erithizon dorsatus), five Long-fronted 

 Gerbilles (Gerbillus longifrons), two Variegated Sheldrakes 

 (Tadorna variegata), bred in the Gardens. 



OUR ASTRONOMICAL COLUMN 



The Approaching Return of Olbers' Comet. — Now that 

 the comet of Pons is drawing away from us, attention may be 

 directed to another comet belonging to the same group as regards 

 length of revolution, viz. that discovered by Olbers at Bremen 

 on March 6, 1S15, and last observed by Gauss at Gottingen on 

 August 25. While it was still under observation an elliptic orbit 

 was assigned by several astronomers, including Bessel and Gauss, 

 who found the period between seventy and eighty years. Bessel 

 subsequently discussed all the observations available to him, in a 

 memoir published in the Transactions of the Berlin Academy, 

 and, after determining the most probable orbit in 1815, he calcu- 

 lated the planetary perturbations to the time of ensuing return to 

 perihelion, which he fixed to 1887, February 9, the effect of the 

 perturbations being to accelerate the return by about 825 days. 



An elaborate investigation of the elements of Olbers' comet 

 and the effects of planetary attraction during the current revolu- 

 tion has been lately made by Herr F. K. Ginzel, of Vienna : it 

 gained the prize of the Haarlem Society of Sciences, and was 

 published by the Society in 1SS1. The author has availed him- 

 self of the improved values of the planetary masses and the other 

 advantages which the astronomy of the last seventy years has 

 placed in our hands, and has produced an interesting and skil- 

 fully-worked discussion of the motion of the comet since it passed 

 out of view in 1815. He commences with a solar ephemeris, and 

 coordinates X, Y, Z, founded upon Leverrier's Tables, and ex- 

 tending from March 4 to August 27, followed by an ephemeris 

 from Bessel's ellipse of the comet's geocentric right ascension and 

 declination and log. distance for the same period. In the next 

 section the observations are as far as possible newly reduced, 

 great care and trouble having been bestowed on the determina- 

 tion of the places of the comparison stars from the most reliable 

 catalogues. It may be mentioned that there are observations at 

 fourteen observatories, including Greenwich, where the comet 

 was followed from May 22 to July 7 ; the series newly reduced 

 are those of Berlin, Gottingen, Konigsberg, Paris, Prague, and 

 Seeberg. The necessary data for reduction of mean to apparent 

 places of the comparison stars follow. The effect of parallax is 

 applied to the comet's observed positions, and we have then the 

 entire collection of deduced geocentric places, with the Berlin 

 mean times of the observations. 



In Bessel's investigation 187 observations were utilised ; Ginzel 

 has the greatly increased number of 346. The perturbations of 

 Mercury, Venus, the Earth, Mars, Jupiter, Saturn, Uranus, and 

 Neptune are next calculated for the period over which tire obser- 

 vations extend ; twelve normal positions are formed, and cleared 

 of the effect of planetary attraction ; then, in the usual manner, 

 Bessel's elements are corrected by equations of condition, and 

 the following definitive orbit for 1815 is obtained : — 



Perihelion passage, 1815 April 26-030146 Berlin M.T. 



M.Eq. 

 1815-0 



Longitude of perihelion 149 2 2-8 



,, ascending node 83 28 467 



Inclination 44 29 50-8 



Eccentricity 0-93114958 



Log. perihelion distance 0-0837998 



Hence there results a revolution of nearly 74 years. The limits 

 of uncertainty in this period are then examined, and found to be 

 75 '6S and 72-33 years, and thus Ginzel concludes that the time 

 of revolution given by the complete discussion of the observations 

 of 1815 is in doubt to the extent of I "6 year, or about a year and 

 seven months. 



In the next section of the memoir are presented the details of 

 the laborious work involved in the calculation of the effect of 

 planetary attraction during the actual revolution. The separate 

 effect of each of the planets Jupiter, Saturn, Uranus, and Neptune 



